A motor used to drive an electric car, particularly an electric vehicle and a hybrid electric vehicle, is desired to be small, light, and highly efficient. In recent years, by development of a highly efficient magnet material, as a drive motor for an electric car (particularly an electric vehicle and a hybrid electric vehicle), in consideration of the respect that it can be made smaller, lighter, and more highly efficient than an induction motor and a reluctance motor, a permanent magnet motor has been used predominantly. The reason is that the permanent magnet motor can generate a large amount of magnetic flux without supplying a large current. Particularly, in a region of high torque at a low speed, the characteristic can be realized. On the other hand, at a high speed, an occurrence of iron loss and an occurrence of high voltage due to the magnetic flux amount often come into a problem.
As a rotor structure of a motor used for an electric car, particular an electric vehicle and a hybrid electric vehicle, in consideration of countermeasures for an occurrence of iron loss and an occurrence of high voltage and retention of permanent magnets, an embedding type permanent magnet rotating electric machine for embedding permanent magnets in a laminated silicone steel plate is known. Furthermore, as described in Japanese Patent Laid-Open No. Hei09(1997)-261901, as a structure of reducing the rate of torque by magnets and reducing the magnetic flux amount of permanent magnets, a structure of arranging auxiliary salient poles between permanent magnets is known. In this structure, since the magnetic flux of the permanent magnets is little, the iron loss at a comparatively high speed is little, while in a region requiring low speed torque, reluctant torque is produced by the auxiliary salient poles and little magnetic torque can be compensated for.